Fix a crash when typing in an exo window.

chrome/browser/ui/views/ime_driver/input_method_bridge_chromeos.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/views/ime_driver/input_method_bridge_chromeos.h"
 
 #include "chrome/browser/ui/views/ime_driver/remote_text_input_client.h"
 
 InputMethodBridge::InputMethodBridge(ui::mojom::TextInputClientPtr client)
     : client_(base::MakeUnique<RemoteTextInputClient>(std::move(client))),
@@ skipping 21 matching lines @@
 
 void InputMethodBridge::ProcessKeyEvent(
     std::unique_ptr<ui::Event> event,
     const ProcessKeyEventCallback& callback) {
   DCHECK(event->IsKeyEvent());
   ui::KeyEvent* key_event = event->AsKeyEvent();
   if (!key_event->is_char()) {
     input_method_chromeos_->DispatchKeyEvent(
         key_event, base::MakeUnique<base::Callback<void(bool)>>(callback));
   } else {
-    callback.Run(false);
+    // On Linux (include ChromeOS), the mus emulates the WM_CHAR generation

[sky, 2016/12/15 16:54:14]

This seems like a work around. Unnecessarily consuming events means other parts
of the system might not get them. Can't exo filter the events out if it doesn't
want them?

[Peng, 2016/12/15 17:24:36]

On Window, the char events are consumed by InputMethodWin[1]. So seems on other
platforms, the IME should consumes those char events too. But
InputMethodChromeOS doesn't expect char events, so I think the IME bridge should
filter them out. And see [2] [3] [4], looks like other parts of system do not
expect char events too.


[1]
https://cs.chromium.org/chromium/src/ui/base/ime/input_method_win.cc?sq=packa...
[2]
https://cs.chromium.org/chromium/src/ui/views/mus/native_widget_mus.cc?rcl=14...
[3]
https://cs.chromium.org/chromium/src/ui/views/widget/desktop_aura/desktop_nat...
[4]
https://cs.chromium.org/chromium/src/ui/wm/core/accelerator_filter.cc?rcl=148...

+    // behaviour of Windows. But for ChromeOS, we don't expect those char
+    // events, so we filter them out.
+    const bool handled = true;
+    callback.Run(handled);
   }
 }
 
 void InputMethodBridge::CancelComposition() {
   input_method_chromeos_->CancelComposition(client_.get());
 }